Composting is a microbial process that converts plant
materials such as grass clippings and leaves to a usable
organic soil amendment or mulch. Gardeners have used
compost for centuries to increase soil organic matter,
improve soil physical properties and supply some of the
essential nutrients for plant growth. Incorporating compost
into light, sandy soil helps it hold both moisture and
nutrients, while adding it to heavy soil improves drainage.
Several conditions must be met to produce compost
efficiently from yard waste. The micro-organisms
responsible for decomposition need oxygen, water and
nitrogen. Particle size also affects efficiency. The smaller
the plant pieces, the more rapidly they will break down. Use
a shredder or power mower to chop leaves and little twigs
into smaller bits before adding them to the pile.
Composting structures
To save space, keep your yard looking neat and speed
composting time, place your compost in an enclosed
container. City Code requires composting to be conducted
within an enclosed container not to exceed a total of 100
cubic feet in volume for city lots less than 10,000 square
feet and 150 cubic feet for lots greater than 10,000 square
feet. The container must be of a durable material such as
wood, block, sturdy metal fencing or rigid plactic.
Typical dimensions of a
compost pile are five-by-five-
by-five foot (125 cubic feet).
Simple bin type structures
can be built from woven wire
fencing and metal posts.
More permanent and
elaborate structures can be made from rot-resistant wood,
wire and metal posts or purchased at your local gardening
store. There are many possible structures for composting;
no one structure is best.
Compost pile placement
Locate your compost pile close to where it will be used so it
won’t interfere with activities in the yard or offend
neighbors. The pile will do best where it is somewhat
protected from drying winds, yet receives partial sunlight to
help heat it.
Bloomington ordinances require compost piles to be
screened from your neighbors’ view. Locate your compost
pile at least 10 feet from your lot lines, 5 feet from an alley
and no closer than 50 feet from a neighbor’s house. The
illustration above shows a typical lot.
If you have questions about the required screening in
Bloomington, contact the Environmental Health Division at
952-563-8934.
Avoiding unpleasant odors
Odors may arise from the addition of excessive amounts of
wet plant materials like fruits or grass clippings,
overwatering the pile or not turning an actively
decomposing pile periodically.
C
ompost needs to be turned
over and mixed within the container in order to keep the
material aerated, to minimize odor generation and promote
effective decomposition of the material. A properly
prepared and adequately turned compost heap will
generate little if any objectionable odor.
Also, keeping the compost damp but not waterlogged will
go along way toward preventing unpleasant odors. Adding
lime does not necessarily reduce odors and may result in
the loss of nitrogen from the pile.
Backyard Composting
Information Handout
Community Development
Environmental Health
1800 W. Old Shakopee Road
Bloomington MN 55431-3027
PH 952-563-8934
FAX 952-563-8949
TTY 952-563-8740
www.ci.bloomington.mn.us
57scompost pg1 of 2 (06/04)
Woven wire
fencing
(4' - 5' High)
Chain snaps
YOUR HOME
HOUSE
Lot Line
10'
50'
10'
STREET
SCREENED
COMPOST PILE
Preparing a compost pile
Build your compost pile in layers. Begin with eight to ten
inches of leaves, grass or plant trimmings. Water it to the
point of being moist, but not soggy. Then add a nitrogen
source, such as ammonium nitrate, ammonium sulfate or
an inexpensive high nitrogen lawn fertilizer without
herbicide.
You may choose to add a one-inch layer of soil or
completed compost over the nitrogen to increase the
number of decomposing microbes. However, most leaves
and plant scraps have enough micro-organisms to get the
job done without the addition of soil or compost.
Repeat these layers until the pile reaches a height of five
feet, watering each time you add new layers.
What can be composted
Many organic materials can be composted besides grass
and leaves; non-woody shrub trimmings or twigs less than
1/4 inch in diameter, faded flowers, weeds, garden and
aquatic plants, straw, shredded newspaper (black and
white print), and small amounts of wood ash and sawdust.
Sawdust requires the addition of extra nitrogen; wood ash
raises compost alkalinity.
There should be little need to compost grass, since
clippings may be left safely on the lawn if you mow
regularly whenever grass blades are 1/3 longer than the
desired height. If you do compost grass, mix it with other
yard waste to aid decomposition and reduce any odors.
Grass clippings, alone, pack down and restrict air flow.
Some things should not be composted. Pet feces can
transmit diseases. Meat, bones, grease, whole eggs and
dairy products attract rodents and other animals. Badly
diseased or insect-infested plants and weeds that are
loaded with seed may not heat up enough to be rendered
harmless.
Liming
It is normally not necessary
to add lime to your pile to
improve the break-down of
most yard wastes. Finished
compost is usually slightly
alkaline; if you add lime
during the decomposition
process, it will probably be
too alkaline when completed.
If your pile contains large
amounts of acidic materials
such as pine needles or fruit
wastes, you might add lime,
but no more than one cup per 25 cubic feet of material.
Excessive lime application can lead to loss of nitrogen
from the compost pile.
Maintaining a compost pile
An active compost pile will heat up 130 to 160°F in the
middle. As the center cools, turn the pile to help speed
decomposition, perhaps once or twice a month. This also
minimizes any objectionable odors. Continue to water it
periodically to keep the pile moist but not soggy.
You can add a little fresh material when you turn the pile,
but generally, you’re better off beginning a new pile. A well-
managed compost pile will be ready in two to four months
in the warm season, whereas an untended pile may take
over a year to decompose. When complete, a compost pile
will be about half its original height and will have a
pleasant, earthy smell.
For detailed information or questions about composting,
contact the Hennepin County Extension Service or the
Bloomington Solid Waste Section, 952-563-8750,
TTY: 952-563-8740.
For specific regulations see
Bloomington City Code,
Sections 10.04 and 10.05
or call Environmental Health at
952-563-8934.
Sources: Robert J. Mugaas, County Extension Agent,
Horticulture, Minnesota Extension Service-Hennepin
County, and Deborah L. Brown, Extension Horticulturist
Service.
Additional references: “The Complete Book of
Composting,” J.I. Rodale, Rodale Books, Inc.
57scompost pg2 of 2 (07/04)
PLEASE
RECYCLE
Nitrogen source
Yard waste
Leaves, grass and plant trimmings,
dampened with water.
Soil or completed compost
